The present invention relates, in general, to apparatus for adhesively securing veneer or banding material to boards and panels, and more particularly, relates to an apparatus and method for adhesively securing banding material strips to the edges of a board or panel.
In many furniture applications, boards or panels, and particularly veneer-covered boards and panels, have an edge strip of banding material secured to the edges of the board or panel to prevent unsightly edges from being exposed in the final product. Typically such edge banding strips are adhesively secured, usually hot-glued, to the board or panel edge by an edge banding apparatus or machine.
The board or panel may be a wooden member or a composite member and may, or may not, have a veneer layer on one of the front and/or back surfaces thereof. As used herein, however, the expression xe2x80x9cboardxe2x80x9d shall include wooden and composite substrates, members, panels or boards, and may even include plastic substrates. Such xe2x80x9cboardsxe2x80x9d may or may not include front and/or rear surface veneer layers on them.
Prior art edge banding apparatus typically are formed to support the board to be edge banded in a generally horizontal orientation. They include applicator assemblies which apply adhesive, usually hot adhesive, to a generally vertically oriented edge of the horizontal board from an adhesive reservoir having a heating element in the reservoir. Since the adhesives most commonly used must be heated to a very high temperature, for example, 200xc2x0 C., handling of the hot adhesive is difficult and dangerous.
There are constant problems with hot adhesive slump or running off of the adhesive from the adhesive applicator and/or the board edge. Usually a roller or dispensing wheel mounted to rotate about an horizontal axis is used to apply the hot adhesive, and compensating for adhesive slump can be difficult. Other adhesive handling problems arise when using prior edge banding equipment. Thus, changing adhesive colors and refilling the adhesive reservoir have both caused safety and time consumption problems.
Still further, such prior art edge horizontal banding devices have required considerable floor space, for example, in order to support a horizontally oriented 4 foot by 8 foot panel during edge banding. Panel or board handling using prior art apparatus also has not been very ergonomic, causing undue worker fatigue. Additionally, in wood-working or furniture manufacturing facilities, wood dust is a serious problem, and prior art edge banding apparatus have had many horizontal surfaces on which dust and debris can accumulate.
Another problem encountered in prior art edge banding apparatus has been that the rough trim or banding material cutoff assembly has been either a scissors or guillotine type of device which can present a safety hazard. These trim devices typically project a cutting blade through the direction of travel of the board to create a pinch point which cannot be well guarded.
Accordingly, it is an object of the present invention to provide an edge banding apparatus and method which is more ergonomic, has more uniform and reliable adhesive application, and is easier and safer to operate.
Another object of the present invention is to provide an edge banding apparatus which requires less floor space, has fewer horizontally oriented dust-collecting surfaces and employs the weight of the board being edged to enhance securement of the banding material to the board edge.
Still another object of the present invention is to provide an apparatus and method for sensing the level of adhesive in a relatively small adhesive reservoir for the edge banding apparatus and to periodically automatically refill the adhesive reservoir based upon the level sensed.
Another object of the present invention is to provide an adhesive applying assembly in which the adhesive reservoir and heating device are separable elements.
A further object of the present invention is to provide an improved adhesive dispensing assembly and method for dispensing adhesive in an edge banding apparatus.
It is also an object of the present invention to provide a banding material cutoff assembly or rough trim device which can cutoff the edge banding material without exposing the operator to a safety hazard.
The edge banding apparatus and method of the present invention have other objects and features of advantage which will be set forth in more detail in, or will be apparent from, the following Best Mode of Carrying Out the Invention and the accompanying drawing.
The edge banding apparatus of the present invention comprises, briefly, a board support structure formed to support a board to be edge-banded in a near vertical orientation with an edge of the board to be banded in a downwardly facing orientation, an adhesive applying assembly positioned relative to the board support structure and formed to apply adhesive to the downwardly facing edge during relative movement between the board and the adhesive applying assembly, and a banding material applying assembly formed to apply a banding material to the board edge after application of the adhesive and during relative movement between the board and the banding material applying assembly. In the preferred embodiment the board is supported on the board support structure for movement of the board and downwardly facing edge over the top of a roller adhesive applicator and over the top of a banding material applying roller. Subsequent pressing rollers press the applied banding material against the adhesive on the board edge using the weight of the board to effect such pressing.
In another aspect of the invention, a pneumatic sensing apparatus is provided to sense the level of viscous adhesive in an adhesive reservoir of the edge banding apparatus in order that the reservoir can be periodically refilled. Moreover, a pneumatically operated granular adhesive dispensing assembly is coupled to receive signals from the level sensing apparatus in order to refill the adhesive reservoir.
The method of adhesively securing a banding material to the edge of a board of the present invention is comprised, briefly, of the steps of orienting the board to be edge-banded in a substantially vertical orientation with the edge to be banded facing downwardly, applying adhesive to the downwardly facing edge during relative movement between the board and an adhesive applicator, thereafter applying a banding material to the downwardly facing edge over the adhesive, and pressing the banding material against the edge, preferably by using, in part, the weight of the board against a pressing surface, such as pressing rollers.
Methods of pneumatic adhesive level sensing and pneumatic adhesive dispensing also are provided.